Boat hulls

ABSTRACT

A boat hull, part of which (preferably the forward section) is shaped as a twin keel, and part of which (preferably the rearward section) is shaped as a single keel.

Unite States Patent [191 English et al.

[ 1 BOAT HULLS [76] Inventors: Keith William English, 42 St. Helen Park Rd., Hastings; .lohn Reginald Filmer, Little Walstead Farm, Lindfield, both of England [22] Filed: Apr. 19, 1971 [21] Appl. No.: 135,191

[52] US. Cl. 114/56, 114/61, 114/66.5 R [51] Int. Cl 1363b l/04 [58] Field of Search 114/61, 66.5 R, 66.5 S, 114/56 [56] References Cited UNITED STATES PATENTS Wolfe et al. l14/66.5 S

[ Apr. 30, 1974 2,995,104 8/1961 Mills 1l4/66.5 S 3,469,549 9/1969 Rae 1l4/66.5 R 2,989,939 6/1961 Tatter 114/56 Primary Examiner-Trygve M. Blix Assistant ExaminerStuart M. Goldstein Attorney, Agent, or Firm-Schapp and Hatch [5 7] ABSTRACT A boat hull, part of which (preferably the forward section) is shaped as a twin keel, and part of which (preferably the rearward section) is shaped as a single keel.

5 Claims, 3 Drawing Figures BOAT HULLS The present invention relates to boat hulls.

Many types of hulls are known and these can be summarised as follows:

1. Single keel, one hull craft, which may be stepped,

2. Catamaran twin separated hulls, which may be stepped,

3. Triple keel, single hull craft, sometimes referred to as Cathedral,

4. Twin keel, single hull with a tunnel from bow to stern,

5. Cathedral type bow (see (3) above) with the centre hull diminishing to leave a clear tunnel for the remainder of the hull length,

6. A hull with outboard flotation pods attached to the hull by spars,

7. A hull with sponsons attached thereto.

summarising, it can be concluded that single-keel craft are more manoeuverable and have a better planing aspect ratio than multi-hull craft. Furthermore, single-keel craft are not subject to the high structural stresses as multi-hull craft are. However, single-keel craft are far less stable than multi-hull craft and, for comparable lengths, have considerably less deck area.

An object of the present invention is to provide a craft hull combining-the stability and spaciousness of multiple hull craft with the planing characteristics and manoeuverability of single hull craft.

The invention provides a boat hull, part of which is shaped as a twin keel, and part of which is shaped as a single keel.

Preferably, the forward section is a twin keel and the rearward section is a single keel.

The invention will be further described with reference to an embodiment shown by way of example in the accompanying drawing wherein:

FIGS. 1, 2 and 3 are side, front and underneath views, respectively, of the embodiment of the hull.

In the drawing, a boat hull is formed from a twin keel front section 2 having two keels 3 and 4 and a rear section 5 having a single keel 6.

When planing the hull rides on the points 7 in FIG. 3 and this three-point contact with the water gives great stability in all seas.

Improved vertical acceleration properties are obtained by the wide-apart spacing of the twin bow keels 3, 4. This forms cavitation which having provided cushioning and lift to the front section 2 is expelled to the side of the hull to the rear of the twin keels 3, 4, thus keeping the propeller (not shown) relatively clear of all cavitation.

Since the hull is a one piece structure high stress areas are avoided.

Various embodiments may be made within the scope of the invention.

Thus the keels 3 and 4 may be provided as lowering and raising sections to improve riding characteristics of the hull according to pay loadings and the water surface being encountered.

Alternatively, keel extensions to keels 3 and 4 may be provided to suit such items as pay loadings and engine sizes.

Spray rails can be added designed to gain lift and reduce skin friction.

The single keel 6 may have a drop centre board or built-in keel extension to enable the craft to be sailed.

The flat surface between the two keels 3 and 4 may be perforated and air drawn through these perforations and out of the rear of the hull using the partial vacuum formed at the rear, thus preventing excessive frontal lift on craft where high speeds are required.

The hovercraft principle may be added to any part of the hull to give manoeuverability in lower water draft areas.

Wheels (retractable or otherwise) may be added to make the vehicle amphibious.

The number of forward, or forward and rear, sections can be increased by repetition of the design to increase the beam measurement.

We claim:

1. A boat hull comprising a one-piece structure having a substantially rectangular shape, and formed with two keels at the forward section of the hull extending rearwardly to approximately halfway only along the hull, a single keel at the rearward section of the hull extending forwardly to approximately halfway along the hull, said single keel extending longitudinally centrally of the hull and extending laterally of the hull over substantially the whole width of the hull rearwardly of the said two keels, and all three keels having a substantially V shaped cross-section.

2. A boat hull comprising a one-piece structure having a substantially rectangular shape, and formed with two keels at the forward section of the hull extending rearwardly to approximately halfway along the hull, a single keel at the rearward section of the hull extending forwardly to approximately halfway along the hull, said single keel extending centrally of the hull, and all three keels having a substantially V shaped cross-section, said boat hull also having two inclined side portions, with the two keels at the forward end each have one arm of their substantially V shaped cross-section planar with one of said inclined side portions and being inclined to the vertical at a sharper angle than the other arm of the V.

3. A boat hull as defined in claim 2, in which the single keel has both arms of its V shaped cross-section extending upwardly tosaid side portions.

4. A boat hull as defined in claim 3, in which each of the three keels extend rearward and downward to provide a lowest point on each keel at its rearmost location.

5. A boat hull comprising a one-piece structure having a substantially rectangular shape with two inclined side portions, and formed with two forward keels at the forward section of the hull extending rearwardly and progressively downwardly to approximately halfway along the hull, and a single keel at the rearward section of the hull extending forwardly and progressively up wardly to approximately halfway along the hull, said two forward keels each having a substantially V shaped cross-section with one arm substantially planar with one of said inclined side portions and being inclined to the vertical at a sharper angle than the other arm, and said single keel having a V shaped crosssection with both arms of the V extending upwardly to said side portions. 

1. A boat hull comprising a one-piece structure having a substantially rectangular shape, and formed with two keels at the forward section of the hull extending rearwardly to approximately halfway only along the hull, a single keel at the rearward section of the hull extending forwardly to approximately halfway along the hull, said single keel extending longitudinally centrally of the hull and extending laterally of the hull over substantially the whole width of the hull rearwardly of the said two keels, and all three keels having a substantially V shaped cross-section.
 2. A boat hull comprising a one-piece structure having a substantially rectangular shape, and formed with two keels at the forward section of the hull extending rearwardly to approximately halfway along the hull, a single keel at the rearward section of the hull extending forwardly to approximately halfway along the hull, said single keel extending centrally of the hull, and all three keels having a substantially V shaped cross-section, said boat hull also having two inclined side portions, with the two keels at the forward end each have one arm of their substantially V shaped cross-section planar with one of said inclined side portions and being inclined to the vertical at a sharper angle than the other arm of the V.
 3. A boat hull as defined in claim 2, in which the single keel has both arms of its V shaped cross-section extending upwardly to said side portions.
 4. A boat hull as defined in claim 3, in which each of the three keels extend rearward and downward to provide a lowest point on each keel at its rearmost location.
 5. A boat hull comprising a one-piece structure having a substantially rectangular shape with two inclined side portions, and formed with two forward keels at the forward section of the hull extending rearwardly and progressively downwardly to approximately halfway along the hull, and a single keel at the rearward section of the hull extending forwardly and progressively upwardly to approximately halfway along the hull, said two forward keels each having a substantially ''''V'''' shaped cross-section with one arm substantially planar with one of said inclined side portions and being inclined to the vertical at a sharper angle than the other arm, and said single keel having a ''''V'''' shaped cross-section with both arms of the ''''V'''' extending upwardly to said side portions. 